Upload to AWS S3 then recheck content with md5 hash

s3_upload.py

import os
import boto3
import botocore
import hashlib

def md5sum(filepath):
    hash = hashlib.md5()
    with open(filepath, "rb") as f:
        for chunk in iter(lambda: f.read(128 * hash.block_size), b""):
            hash.update(chunk)
    return hash.hexdigest()
  
def upload_file(s3_client, bucket=None, key=None, filepath=None, storage_class='STANDARD', retry=3):
  etag = None
  while retry > 0:
    try:
      response = s3_client.upload_file(
        filepath, 
        bucket, 
        key, 
        ExtraArgs={
          'StorageClass': storage_class, 
          'Metadata': {
            'namehash': os.path.basename(filepath),
            'mode': 'encrypted'
          }
        }
      )
      if not response:
        etag = s3_client.head_object(Bucket=bucket, Key=key)['ETag'].strip('"')
    except botocore.exceptions.ClientError as exc:
        raise Exception('file uploaded client error') from exc
    except Exception as exc:
      raise Exception('file uploaded cannot fail') from exc

    checksum = md5sum(filepath)
    if checksum == etag:
      return "{}/{}/{}".format(s3_client.meta.endpoint_url, bucket, key)
    else:
      if retry <= 0:
        raise Exception('file uploaded checksum mismatch {} after {} retry'.format(object_url, retry))
      
    retry = retry - 1
    
    
s3_client = boto3.client(
    's3',
    endpoint_url="https://{}".format(config.get(source, 'Endpoint')),
    aws_access_key_id = config.get(source, 'AccessKey'),
    aws_secret_access_key = config.get(source, 'SecretKey'),
    verify=False, config=botocore.config.Config(
      max_pool_connections=max_pool,    
      retries = {'max_attempts': retry, 'mode': 'standard'})
  )
upload_file(s3_client, bucket="TEST", key="FILE", filepath="LOCALFILE", storage_class='STANDARD', retry=3):